|Publication number||US7108751 B2|
|Application number||US 10/739,126|
|Publication date||Sep 19, 2006|
|Filing date||Dec 19, 2003|
|Priority date||Dec 20, 2002|
|Also published as||US7384876, US20040129217, US20060138082, WO2004061888A2, WO2004061888A3|
|Publication number||10739126, 739126, US 7108751 B2, US 7108751B2, US-B2-7108751, US7108751 B2, US7108751B2|
|Inventors||Eric J. Strang|
|Original Assignee||Tokyo Electron Limited|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (17), Non-Patent Citations (1), Classifications (21), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application claims priority to and is related to U.S. Provisional Application Ser. No. 60/434,657, filed on Dec. 20, 2002. The entire content of this application is incorporated herein by reference.
The present invention relates to a method and apparatus for determining consumable lifetime in an erosive environment, and more particularly to a method and apparatus for determining the lifetime of a consumable gas injection component.
In semiconductor manufacturing, plasma is often employed to create and assist surface chemistry within a plasma reactor necessary to remove material from and deposit material to a substrate. In general, plasma is formed within the plasma reactor under vacuum conditions by heating electrons to energies sufficient to sustain ionizing collisions with a supplied process gas. Moreover, the heated electrons can have energy sufficient to sustain dissociative collisions and, therefore, a specific set of gases under predetermined conditions (e.g., chamber pressure, gas flow rate, etc.) are chosen to produce a population of charged species and chemically reactive species suitable to the particular process being performed within the chamber (e.g., etching processes where materials are removed from the substrate or deposition processes where materials are added to the substrate). One pre-requisite to ensuring a uniform process includes a uniform injection of process gas to the plasma chemistry above the substrate.
A method and apparatus are described for determining consumable lifetime, and particularly a method and apparatus for determining a lifetime of a consumable gas injection component.
More particularly, a gas injection system in a plasma processing device is described comprising: a gas injection assembly body configured to receive a process gas from one or more mass flow controllers; a consumable gas inject plate coupled to the gas injection assembly body, the consumable gas inject plate comprising one or more orifices to distribute the process gas to the plasma processing device; a pressure sensor coupled to the gas injection assembly body and configured to measure a gas injection pressure within a gas injection plenum formed by the gas injection assembly body and the consumable gas inject plate; and a controller coupled to the pressure sensor and configured to determine a state of the consumable gas inject plate from a change in the gas injection pressure.
Additionally, a method of determining the state of a gas injection system in a plasma processing device comprises: changing a process parameter in the plasma processing device to affect a change of a gas injection pressure in the gas injection; measuring a response time corresponding to a change of the gas injection pressure using the pressure sensor, wherein the response time corresponds to a first time duration when the consumable gas inject plate has not been eroded and the response time corresponds to a second time duration when the consumable gas inject plate has been eroded; and comparing the response time to at least one of the first and second time durations in order to determine the state of the gas injection system.
These and other advantages of the invention will become more apparent and more readily appreciated from the following detailed description of the exemplary embodiments of the invention taken in conjunction with the accompanying drawings, where:
A plasma processing device 100 is depicted in
According to the illustrated embodiment depicted in
Substrate 125 can be, for example, affixed to the substrate holder 120 via an electrostatic clamping system. Furthermore, substrate holder 120 can, for example, further include a cooling system including a re-circulating coolant flow that receives heat from substrate holder 120 and transfers heat to a heat exchanger system (not shown), or when heating, transfers heat from the heat exchanger system. Moreover, gas can, for example, be delivered to the back-side of substrate 125 via a backside gas system to improve the gas-gap thermal conductance between substrate 125 and substrate holder 120. Such a system can be utilized when temperature control of the substrate is required at elevated or reduced temperatures. For example, the backside gas system can comprise a two-zone gas distribution system, wherein the helium gas gap pressure can be independently varied between the center and the edge of substrate 125. In other embodiments, heating/cooling elements, such as resistive heating elements, or thermo-electric heaters/coolers can be included in the substrate holder 120, as well as the chamber wall of the plasma processing chamber 110 and any other component within the plasma processing device 100.
In the illustrated embodiment, shown in
Alternately, RF power is applied to the substrate holder electrode at multiple frequencies. Furthermore, impedance match network 150 serves to maximize the transfer of RF power to plasma in plasma processing chamber 110 by minimizing the reflected power. Match network topologies (e.g. L-type, π-type, T-type, etc.) and automatic control methods are well known to those skilled in the art.
Vacuum pump system 130 can, for example, include a turbo-molecular vacuum pump (TMP) capable of a pumping speed up to 5000 liters per second (and greater) and a gate valve for throttling the chamber pressure. In conventional plasma processing devices utilized for dry plasma etch, a 1000 to 3000 liter per second TMP is generally employed. TMPs are useful for low pressure processing, typically less than 50 mTorr. At higher pressures, the TMP pumping speed falls off dramatically. For high pressure processing (i.e., greater than 100 mTorr), a mechanical booster pump and dry roughing pump can be used. Furthermore, a device for monitoring chamber pressure (not shown) can be coupled to the plasma processing chamber 110. The pressure measuring device can be, for example, a Type 628B Baratron absolute capacitance manometer commercially available from MKS Instruments, Inc. (Andover, Mass.).
Controller 114 comprises a microprocessor, memory, and a digital I/O port capable of generating control voltages sufficient to communicate and activate inputs to plasma processing device 100 as well as monitor outputs from plasma processing device 100. Moreover, controller 114 can be coupled to and can exchange information with RF generator 140, impedance match network 150, the gas injection system 101, diagnostic system 112, vacuum pump system 130, as well as the backside gas delivery system (not shown), the substrate/substrate holder temperature measurement system (not shown), and the electrostatic clamping system (not shown). For example, a program stored in the memory can be utilized to activate the inputs to the aforementioned components of plasma processing device 100 according to a process. In addition, controller 114 can be configured to receive one or more signals from the diagnostic system 112, process the one or more signals, and determine a state of the gas injection system 101 and its consumable components. One example of controller 114 is a DELL PRECISION WORKSTATION 610™, available from Dell Corporation, Austin, Tex.
In the illustrated embodiment, shown in
In the illustrated embodiment, shown in
In the illustrated embodiment, shown in
Alternately, the plasma can be formed using electron cyclotron resonance (ECR). In yet another embodiment, the plasma is formed from the launching of a Helicon wave. In yet another embodiment, the plasma is formed from a propagating surface wave. Each plasma source described above is well known to those skilled in the art.
Referring now to
The pressure sensor 220 can, for example, be a Type 628B Baratron absolute capacitance manometer commercially available from MKS Instruments, Inc. (Andover, Mass.). As shown in
Alternately, as shown in
Due to the change in orifice length and diameter, the flow conductance C of the orifice(s) 260 changes predominantly in inverse proportion to the length and directly proportional to the diameter to third power for a free molecular flow and to the fourth power for a continuum flow. Therefore, during any change in processing pressure or mass flow rate, the response of the pressure P in the gas injection plenum 216 depends primarily upon the volume of the gas injection plenum 216 (fixed) and the net conductance of the orifice(s) 260 in the consumable gas inject plate 230.
For example, during vacuum pump-down following wafer exchange with the transfer system (not shown) and preceding the initiation of a process gas flow rate, the vacuum pressure within the processing system is reduced (possibly to a base pressure) and, subsequently, the gas injection plenum pressure P is reduced, however, following a delay Δt.
In an alternate embodiment,
In step 520, a response time is determined from a time trace of the gas injection pressure measured using the pressure sensor coupled to the gas injection system, or an nth derivative of the respective time trace. When the one or more orifices of the consumable gas inject plate correspond to a non-eroded state, the response time exhibits a first time delay ΔtA in a first time trace. For example, the consumable gas inject plate has not been eroded when it is either first installed or replaced, and it has yet to be exposed to an erosive environment, such as plasma. When the one or more orifices of the consumable gas inject plate correspond to an eroded state, the response time exhibits a second time delay ΔtB in a second time trace. For example, the consumable gas inject plate has been eroded once it is exposed to an erosive environment, such as plasma, during the processing of one or more substrates in the plasma processing device.
In step 530, the measured response time is compared to the first time delay to determine the state of the consumable gas inject plate of the gas injection system. In general, if one or more orifices of the consumable gas inject plate erode, the measured response time is less than the first time delay. In one embodiment, the state of the consumable gas inject plate comprises a partially eroded state when the measured response time ranges from 25% to 75% of the first time delay. For example, a partially eroded state can require notification of an operator and a recommendation for replacement of the consumable gas inject plate. In another embodiment, the state of the consumable gas inject plate comprises a fully eroded state when the measured response time is less than 25% of the first time delay. (This lower threshold can be considered as a second delay time against which the measured response time can be compared.) For example, a fully eroded state can require immediate notification of an operator and replacement of the consumable gas inject plate.
In an alternate embodiment, a first response time can be measured for a first location on the consumable gas inject plate, and a second response time can be measured for a second location on the consumable gas inject plate. For example, the first location can comprise at least one orifice proximate the center of the consumable gas inject plate, and the second location can comprise at least one orifice proximate the edge of the consumable gas inject plate. The first and second measured response times can be utilized to determine a uniformity of the process for each substrate processed. The resultant uniformity can be monitored from run-to-run, or batch-to-batch, to ensure that the process is performed within acceptable ranges. When a deviation in the process uniformity exceeds a pre-determined threshold, the operator can be notified for system maintenance.
Although only certain exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4640221 *||Oct 30, 1985||Feb 3, 1987||International Business Machines Corporation||Vacuum deposition system with improved mass flow control|
|US4717596 *||Oct 3, 1986||Jan 5, 1988||International Business Machines Corporation||Method for vacuum vapor deposition with improved mass flow control|
|US5150690 *||Apr 20, 1990||Sep 29, 1992||Ortech Corporation||Flow control system|
|US5350480 *||Jul 23, 1993||Sep 27, 1994||Aspect International, Inc.||Surface cleaning and conditioning using hot neutral gas beam array|
|US5368685 *||Mar 24, 1993||Nov 29, 1994||Hitachi, Ltd.||Dry etching apparatus and method|
|US5644463 *||Sep 26, 1994||Jul 1, 1997||University Of Washington||Adaptive sequential controller with minimum switching energy|
|US5754424 *||Feb 27, 1996||May 19, 1998||Melvin; Kenneth P.||System and method for controlling processes|
|US5991705 *||Jul 23, 1997||Nov 23, 1999||Candle Distributed Solutions, Inc.||End-to-end response time measurement for computer programs using starting and ending queues|
|US6030489 *||Jul 1, 1999||Feb 29, 2000||Taiwan Semiconductor Manufacturing Company, Ltd.||Apparatus for controlling etch rate when using consumable electrodes during plasma etching|
|US6282463 *||Nov 30, 1999||Aug 28, 2001||Smc Corporation||Method of selecting pneumatic devices|
|US6752547 *||Oct 28, 2002||Jun 22, 2004||Applied Materials Inc.||Liquid delivery system and method|
|US6837226 *||Jan 31, 2001||Jan 4, 2005||Cummins, Inc.||System for diagnosing EGR valve, actuator and sensor related failure conditions|
|US20040081457 *||Oct 28, 2002||Apr 29, 2004||Applied Materials, Inc.||Liquid delivery system and method|
|US20040129217 *||Dec 19, 2003||Jul 8, 2004||Tokyo Electron Limited||Method and apparatus for determining consumable lifetime|
|US20040244742 *||Jun 5, 2003||Dec 9, 2004||Caterpillar Inc.||Control system and method for engine valve actuator|
|JPH05165777A *||Title not available|
|JPH07121459A *||Title not available|
|1||Liu et al. "An experimental method to dynamically test pressure sensors using a rupture disk", Review of Scientific Instruments. Feb. 2002, vol. 73, No. 2, pp. 459-463, See p. 462.|
|U.S. Classification||118/663, 118/697, 156/345.24, 118/696, 156/345.27, 156/345.26, 118/698, 156/345.25, 118/715, 118/699, 156/345.28, 118/695, 118/712|
|International Classification||H01J37/32, H01L21/306, C23C16/455, C23F1/00|
|Cooperative Classification||H01J37/3244, H01J37/32935|
|European Classification||H01J37/32O2, H01J37/32S4|
|Mar 3, 2010||FPAY||Fee payment|
Year of fee payment: 4
|Feb 19, 2014||FPAY||Fee payment|
Year of fee payment: 8